Abstract

ASL 5000 (IngMar Medical, Pittsburgh, PA, USA) is a widely used computer-controlled active lung model. The model precisely simulates preset mechanical parameters of the respiratory system for a wide range of conventional modes of mechanical ventilation. ASL 5000 lung model fails to simulate the preset mechanical parameters properly for High Frequency Jet Ventilation and for volume control ventilation with a decelerating flow pattern in some ventilators. The unexpected behavior is strongly dependent on the shape of the flow curve, i.e., on the ventilator setting and the ventilator used. The improper behavior occurs for low preset resistances and larger preset compliances of the respiratory system. Even in the case that the ASL 5000 does not simulate the preset mechanical parameters correctly, the delivered tidal volume measured by ASL 5000 is determined very precisely.